One species' entire genome discovered inside...( Scientists at the University of Roch...)

Scientists at the University of Rochester and the J. Craig Venter Institute have discovered a copy of the entire genome of a bacterial parasite residing inside the genome of its host species.

The finding, reported in todays Science, suggests that lateral gene transferthe movement of genes between unrelated speciesmay happen much more frequently between bacteria and multicellular organisms than scientists previously believed, posing dramatic implications for evolution.

Such large-scale heritable gene transfers may allow species to acquire new genes and functions extremely quickly, says Jack Werren, a principle investigator of the study.

The results also have serious repercussions for genome-sequencing projects. Bacterial DNA is routinely discarded when scientists are assembling invertebrate genomes, yet these genes may very well be part of the organisms genome, and might even be responsible for functioning traits.

This study establishes the widespread occurrence and high frequency of a process that we would have dismissed as science fiction until just a few years ago, says W. Ford Doolittle, Canada Research Chair in Comparative Microbial Genomics at Dalhousie University, who is not connected to the study. This is stunning evidence for increased frequency of gene transfer.

It didnt seem possible at first, says Werren, professor of biology at the University of Rochester and a world-leading authority on the parasite, called Wolbachia. This parasite has implanted itself inside the cells of 70 percent of the worlds invertebrates, coevolving with them. And now, weve found at least one species where the parasites entire or nearly entire genome has been absorbed and integrated into the hosts. The hosts genes actually hold the coding information for a completely separate species.

Wolbachia may be the most prolific parasite in the worlda pandemic, as Werren calls it. The bacterium invades a member of a species, most often an inse
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